One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(9,10,12,14)(11,15,16,13)(17,18,22,20)(19,23,21,24)(25,26)(27,28)(29,37)(30,31)(32,33)(34,38)(35,39)(36,40)(9,10,12,14)(11,13,16,15)(17,18)(19,24)(20,22)(21,23)(26,31)(27,33)(34,37)(35,40)(9,10)(11,13)(12,14)(15,16)(17,19,22,21)(18,23,20,24)(25,27)(26,32)(28,31)(29,35)(30,33)(34,39)(36,37)(38,40)(1,2)(3,6)(4,5)(7,8)(9,10)(11,13)(12,14)(15,16)(17,20,22,18)(19,23,21,24)(25,28,30,32)(26,33,31,27)(29,36,38,39)(34,40,37,35)(1,3,4,7)(2,6,5,8)(9,11,12,16)(10,13,14,15)(17,21,22,19)(18,23,20,24)(25,29)(26,34)(27,35)(28,36)(30,38)(31,37)(32,39)(33,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.